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Mechanisms of β 1 integrin‐dependent adherence of granulocytic HL60 to fibronectin
Author(s) -
Bohnsack John F.,
Chang Jukay,
Zhou Xiaoning,
Yednock Ted A.
Publication year - 1995
Publication title -
journal of leukocyte biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.819
H-Index - 191
eISSN - 1938-3673
pISSN - 0741-5400
DOI - 10.1002/jlb.57.4.592
Subject(s) - biology , fibronectin , integrin , immunology , microbiology and biotechnology , extracellular matrix , genetics , receptor
We investigated the mechanism of β 1 integrin‐mediated adherence of stimulated granulocytic HL60 cells to fibronectin using a monoclonal antibody (15/7) that recognizes β 1 integrins only when the recep tors are active for ligand binding. Phorbol myristate ace tate (PMA) stimulated expression of the 15/7 epitope on granulocytic HL60 by nearly fivefold but had an in significant effect on the expression of the epitope on undifferentiated HL60 cells. These results paralleled the effect of PMA on HL60 and granulocytic HL60 adhesion to fibronectin, indicating that activation of β 1 integrins is important for β 1 ‐mediated adherence of granulocytic HL60 cells to fibronectin. Agonists that stimulate α 5 β 1 ‐dependent human polymorphonuclear leukocyte (PMN) adhesion to fibronectin (C5a and PMA) also up‐regulated the 15/7 epitope on purified human PMNs. Although PMA rapidly induces increased levels of filamentous actin (F‐actin) in granulocytic HL60 cells and a decrease in F‐actin levels in undifferentiated HL60 cells, depolymerization of the actin cytoskeleton with cytochalasin B did not affect increased expression of the 15/7 epitope on granulocytic HL60 cells. Cytochalasin B did, however, inhibit granulocytic HL60 adherence to fibronectin by 50%, demonstrating that actin polymeri zation is important for optimal β 1 ‐dependent granulo cytic adherence. J. Leukoc. Biol. 57: 592–599; 1995.